Plasma processing method including cleaning of inside of chamber main body of plasma processing apparatus

ABSTRACT

A time period for cleaning performed to remove a deposit formed within a chamber main body can be reduced. A plasma processing method including the cleaning of an inside of the chamber main body of a plasma processing apparatus is provided. The method includes etching including a main etching of etching an etching target film of a processing target object placed on a stage in a low temperature by generating plasma of a processing gas containing a fluorocarbon gas and/or a hydrofluorocarbon gas; carrying-out the processing target object from a chamber; and cleaning the inside of the chamber main body by generating plasma of a cleaning gas in a state that a temperature of an electrostatic chuck is set to be high.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation application of U.S. patent application Ser. No.15/876,319, filed on Jan. 22, 2018, which claims the benefit of JapanesePatent Application No. 2017-010538 filed on Jan. 24, 2017, the entiredisclosures of which are incorporated herein by reference.

TECHNICAL FIELD

The embodiments described herein pertain generally to a plasmaprocessing method including cleaning of an inside of a chamber main bodyof a plasma processing apparatus.

BACKGROUND

In the manufacture of an electronic device such as a semiconductordevice, an etching target film of a processing target object is etchedby plasma etching. In the plasma etching, the processing target objectis placed on an electrostatic chuck of a stage provided within a chambermain body of a plasma processing apparatus. Then, a processing gas issupplied into a chamber, and plasma is generated as the processing gasis excited.

The etching target film to be etched in the plasma etching may be, forexample, a silicon oxide film, a silicon nitride film, or a multilayeredfilm composed of these films. In the plasma etching of the etchingtarget film such as the silicon oxide film, the silicon nitride film orthe multilayered film of these films, a processing gas containing eitheror both of a fluorocarbon gas and a hydrofluorocarbon gas is used. Forexample, described in Patent Document 1 is a technique of etching asilicon oxide film by plasma of a processing gas containing afluorocarbon gas.

-   Patent Document 1: Japanese Patent Laid-open Publication No.    H10-116822

In the plasma etching of the etching target film such as the siliconoxide film, the silicon nitride film or the multilayered film of thesefilms, if a temperature of the processing target object is low, anetching rate of the etching target film tends to be increased.Accordingly, the plasma etching may be performed in a state that theelectrostatic chuck and the processing target object are set to a lowtemperature. If the plasma etching using the processing gas containingeither or both of the fluorocarbon gas and the hydrofluorocarbon gas isperformed, a deposit is formed within the chamber main body, e.g., on aninner wall surface of the chamber main body and the stage. Therefore, itis required to clean the inside of the chamber main body prior toperforming the plasma etching on an etching target film of anotherprocessing target object after the plasma etching on the etching targetfilm of the previous processing target object is finished. It isdesirable that a cleaning time is short as a long cleaning time maycause a reduction of a throughput of a plasma processing in the plasmaprocessing apparatus.

SUMMARY

In one exemplary embodiment, there is provided a plasma processingmethod (hereinafter, simply referred to as “method”) including cleaningof an inside of a chamber main body of a plasma processing apparatus.The plasma processing apparatus includes the chamber main body, a stageand a temperature control device. An internal space of the chamber mainbody is configured as a chamber. The stage is provided within thechamber. The stage is configured to hold a processing target objectplaced thereon. The temperature control device is configured to adjust atemperature of an electrostatic chuck.

The method includes (i) etching an etching target film of the processingtarget object placed on the electrostatic chuck by generating plasma ofa processing gas containing a fluorocarbon gas and/or ahydrofluorocarbon gas within the chamber (hereinafter, referred to as“etching process”), the etching of the etching target film including amain etching of etching the etching target film in a state that thetemperature of the electrostatic chuck is set to be equal to or lowerthan −30° C. by the temperature control device; (ii) carrying-out theprocessing target object from the chamber after the etching of theetching target film is performed (hereinafter, referred to as“carrying-out process”); and (iii) cleaning the inside of the chambermain body by generating plasma of a cleaning gas containing oxygenwithin the chamber in a state that the temperature of the electrostaticchuck is set to be equal to or higher than 0° C. by the temperaturecontrol device after the carrying-out of the processing target object isperformed (hereinafter, referred to as “cleaning process”).

In the etching process of the method according to the exemplaryembodiment, a deposit containing carbon and fluorine is formed withinthe chamber main body. Though this deposit is removed by the cleaning ofthe inside of the chamber main body with the plasma of the cleaning gas,a removing rate of the deposit is low when the temperature of theelectrostatic chuck is low as being equal to or less than −30° C. Inthis method, since the cleaning process is performed in the state thatthe temperature of the electrostatic chuck is set to be equal to orhigher than 0° C., the removing rate of the deposit is increased.Therefore, according to this method, a time period for the cleaning ofthe inside of the chamber main body is shortened.

The etching process may further include an overetching of etching theetching target film additionally after the main etching is performed.

The method may further include raising the temperature of theelectrostatic chuck by the temperature control device (hereinafter,referred to as “temperature raising process”), in order to raise thetemperature of the electrostatic chuck to be equal to or higher than 0°C. before the cleaning process is performed.

In the exemplary embodiment, the temperature raising process isperformed when the overetching is being performed. In this exemplaryembodiment, since the raising of the temperature of the electrostaticchuck is performed in parallel with the overetching, an additional timeperiod only for raising the temperature of the electrostatic chuck isnot necessary. Thus, a time period from an end of the etching process toa start of the cleaning process is shortened.

The temperature of the electrostatic chuck may be set to be higher than−30° C. and lower than 0° C. when the overetching is being performed. Ifthe temperature of the processing target object when the overetching isbeing performed is higher than the temperature of the processing targetobject when the main etching is being performed, an etching rate of theetching target film by the overetching is reduced. Accordingly,controllability over an etching amount of the etching target film can beimproved. Further, damage on an underlying layer of the etching targetfilm is suppressed.

The method may further include neutralizing the electrostatic chuckafter the etching process is performed and before the carrying-outprocess is performed; and the temperature raising process. Thetemperature raising process is performed when the neutralizing of theelectrostatic chuck is being performed. According to this exemplaryembodiment, the raising of the temperature of the electrostatic chuck isperformed in parallel with the neutralizing of the electrostatic chuckwhich is performed in a period between the etching process and thecarrying-out process. Accordingly, the time period from the end of theetching process to the start of the cleaning process can be shortened.

The stage may include a lower electrode in which a path is formed. Theelectrostatic chuck may be provided on the lower electrode. Thetemperature control device may include a first temperature adjusterconfigured to supply a first heat exchange medium; and a secondtemperature adjuster configured to supply a second heat exchange mediumhaving a temperature higher than a temperature of the first heatexchange medium. The first heat exchange medium may be supplied into thepath of the lower electrode from the first temperature adjuster when themain etching is being performed, and the second heat exchange medium maybe supplied into the path of the lower electrode from the secondtemperature adjuster when the raising of the temperature of theelectrostatic chuck is being performed. According to the presentexemplary embodiment, when starting the temperature raising process, itis possible to switch the heat exchange medium supplied into the path ofthe lower electrode to the heat exchange medium of the high temperatureat a high speed.

The stage may include a heater provided in the electrostatic chuck and acooling table in which a path is formed. The electrostatic chuck may beprovided on the cooling table. A sealed space may be provided betweenthe electrostatic chuck and the cooling table. The temperature controldevice may include the heater of the electrostatic chuck; a chiller unitconfigured to supply a coolant into the path; and a pipeline systemconfigured to connect one of the chiller unit, a gas exhaust device anda source of a heat transfer gas to the sealed space selectively. Thecoolant may be supplied into the path of the cooling table from thechiller unit and the coolant is supplied into the sealed space from thechiller unit when the main etching is being performed. The electrostaticchuck may be heated by the heater and the sealed space is decompressedby the gas exhaust device when the temperature raising process is beingperformed. In this exemplary embodiment, since heat resistance in thespace between the electrostatic chuck and the cooling table is increasedwhen the temperature raising process is being performed, heat transferbetween the cooling table and the electrostatic chuck is suppressed.Further, the electrostatic chuck is heated by the heater when thetemperature raising process is being performed. Accordingly, a timeperiod required to raise the temperature of the electrostatic chuck isshortened.

According to the exemplary embodiments, it is possible to reduce thetime period for the cleaning performed to remove the deposit formedwithin the chamber main body.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the detailed description that follows, embodiments are described asillustrations only since various changes and modifications will becomeapparent to those skilled in the art from the following detaileddescription. The use of the same reference numbers in different figuresindicates similar or identical items.

FIG. 1 is a flowchart for describing a plasma processing methodaccording to an exemplary embodiment;

FIG. 2 is a cross sectional view illustrating a part of an example of aprocessing target object;

FIG. 3 is a diagram schematically illustrating a plasma processingapparatus that can be used in the method of FIG. 1;

FIG. 4 is a diagram illustrating an example of a temperature controldevice;

FIG. 5 is a timing chart regarding the method shown in FIG. 1;

FIG. 6 is a timing chart regarding the method shown in FIG. 1;

FIG. 7 is a diagram showing a state in which a deposit is formed;

FIG. 8 is a graph showing a result of an experiment;

FIG. 9 is a graph showing a result of an experiment;

FIG. 10 is a diagram showing a state after a process ST7 is performed;

FIG. 11 is a diagram schematically illustrating another example of aplasma processing apparatus that can be used to perform the method ofFIG. 1;

FIG. 12 is an enlarged cross sectional view illustrating a part of astage of the plasma processing apparatus shown in FIG. 11;

FIG. 13 is an enlarged cross sectional view illustrating another part ofthe stage of the plasma processing apparatus shown in FIG. 11; and

FIG. 14 is a diagram illustrating a configuration of an example of apipeline system.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part of the description. In thedrawings, similar symbols typically identify similar components, unlesscontext dictates otherwise. Furthermore, unless otherwise noted, thedescription of each successive drawing may reference features from oneor more of the previous drawings to provide clearer context and a moresubstantive explanation of the current exemplary embodiment. Still, theexemplary embodiments described in the detailed description, drawings,and claims are not meant to be limiting. Other embodiments may beutilized, and other changes may be made, without departing from thespirit or scope of the subject matter presented herein. It will bereadily understood that the aspects of the present disclosure, asgenerally described herein and illustrated in the drawings, may bearranged, substituted, combined, separated, and designed in a widevariety of different configurations, all of which are explicitlycontemplated herein

FIG. 1 is a flowchart for describing a plasma processing methodaccording to an exemplary embodiment. A plasma processing method MT(hereinafter, simply referred to as “method MT”) shown in FIG. 1includes etching an etching target film of a processing target object ina plasma processing apparatus and then cleaning an inside of a chambermain body of the plasma processing apparatus. FIG. 2 is a crosssectional view illustrating a part of an example of the processingtarget object. The method MT is applicable to a processing target objectW shown in FIG. 2.

As depicted in FIG. 2, the processing target object W includes anunderlying layer UL, an etching target film EF and a mask MK. Theunderlying layer UL is a base layer of the etching target film EF and ismade of, by way of non-limiting example, silicon or tungsten. Theetching target film EF is provided on the underlying layer UL. Theetching target film EF may be a silicon oxide film, a silicon nitridefilm or a multilayered film composed of one or more silicon oxide filmsand one or more silicon nitride films stacked on top of each otheralternately. The mask MK is provided on the etching target film EF. Themask MK is made of, but not limited to, a metal such as tungsten,polycrystalline silicon, or an organic material such as amorphouscarbon. The mask MK has an opening. In the method MT, a portion of theetching target film EF exposed through the opening of the mask MK isetched. Further, the mask MK may be provided with multiple openings onthe etching target film EF.

FIG. 3 is a diagram schematically illustrating a plasma processingapparatus that can be used in performing the method of FIG. 1. A plasmaprocessing apparatus 10 shown in FIG. 3 is configured as a capacitivelycoupled plasma processing apparatus. The plasma processing apparatus 10includes a chamber main body 12. The chamber main body 12 has asubstantially cylindrical shape, and an internal space of the chambermain body 12 is configured as a chamber 12 c. The chamber main body 12is made of a metal such as, but not limited to, aluminum. A film havingplasma resistance, for example, an yttrium oxide film is formed on aninner wall surface of the chamber main body 12. The chamber main body 12is grounded.

Within the chamber 12 c, a supporting member 14 is provided on a bottomportion of the chamber main body 12. The supporting member 14 is made ofan insulating material. The supporting member 14 has a substantiallycylindrical shape. Within the chamber 12 c, the supporting member 14 isupwardly extended from the bottom portion of the chamber main body 12.The supporting member 14 is configured to support a stage 16 on an upperportion thereof.

The stage 16 includes a lower electrode 18 and an electrostatic chuck20. The lower electrode 18 includes a first member 18 a and a secondmember 18 b. The first member 18 a and the second member 18 b are madeof a conductor such as, but not limited to, aluminum, and each has asubstantially disk shape. The second member 18 b is provided on thefirst member 18 a and electrically connected with the first member 18 a.The electrostatic chuck 20 is provided on the lower electrode 18.

The electrostatic chuck 20 is configured to hold the processing targetobject W placed thereon. The electrostatic chuck 20 has a substantiallydisk-shaped insulating layer and a film-shaped electrode embedded in theinsulating layer. The electrode of the electrostatic chuck 20 iselectrically connected to a DC power supply 22 via a switch 23. Theelectrostatic chuck 20 attracts and holds the processing target object Wby an electrostatic force generated by a DC voltage applied from the DCpower supply 22. A heater may be provided within this electrostaticchuck 20.

A focus ring FR is provided on a peripheral portion of the lowerelectrode 18 to surround an edge of the processing target object W andan edge of the electrostatic chuck 20. The focus ring FR is provided toimprove uniformity of etching. The focus ring FR is made of a materialwhich is appropriately selected depending on a material of the target ofthe etching.

A path 18 f for a coolant is formed in the second member 18 b of thelower electrode 18. A heat exchange medium is supplied into the path 18f from a temperature control device 24 provided outside the chamber mainbody 12 via a pipeline 25 a. The heat exchange medium supplied into thepath 18 f is returned back into the temperature control device 24through a pipeline 25 b. That is, the heat exchange medium is circulatedbetween the temperature control device 24 and the path 18 f. As the heatexchange medium whose temperature is adjusted is circulated between thetemperature control device 24 and the path 18 f, a temperature of theelectrostatic chuck 20 and, ultimately, a temperature of the processingtarget object W is adjusted.

FIG. 4 is a diagram illustrating an example of the temperature controldevice. As shown in FIG. 4, the example temperature control device 24includes a first temperature adjuster 24 a and a second temperatureadjuster 24 b. The first temperature adjuster 24 a is configured toadjust a temperature of a first heat exchange medium (e.g., brine) andoutput the first heat exchange medium. The second temperature adjuster24 b is configured to adjust a temperature of a second heat exchangemedium (e.g., brine) and output the second heat exchange medium. Thetemperature of the second heat exchange medium is higher than thetemperature of the first heat exchange medium. The first temperatureadjuster 24 a sets therein the temperature of the first heat exchangemedium to, e.g., −70° C. The second temperature adjuster 24 b setstherein the temperature of the second heat exchange medium to be in arange from 0° C. to 100° C.

The temperature control device 24 includes a valve 24 c, a valve 24 d, avalve 24 e and a valve 24 f. An output port of the first temperatureadjuster 24 a is connected to the pipeline 25 a via the valve 24 c. Theoutput port of the first temperature adjuster 24 a is a port foroutputting the first heat exchange medium. A return port of the firsttemperature adjuster 24 a is connected to the pipeline 25 b via thevalve 24 d. The return port of the first temperature adjuster 24 a is aport for receiving the heat exchange medium returned to the firsttemperature adjuster 24 a from the path 18 f through the pipeline 25 b.An output port of the second temperature adjuster 24 b is connected tothe pipeline 25 a via the valve 24 e. The output port of the secondtemperature adjuster 24 b is a port for outputting the second heatexchange medium. A return port of the second temperature adjuster 24 bis connected to the pipeline 25 b via the valve 24 f. The return port ofthe second temperature adjuster 24 b is a port for receiving the heatexchange medium returned to the second temperature adjuster 24 b fromthe path 18 f through the pipeline 25 b.

When circulating the heat exchange medium between the first temperatureadjuster 24 a and the path 18 f, the valve 24 c and the valve 24 d areopened, and the valve 24 e and the valve 24 f are closed. Meanwhile,when circulating the heat exchange medium between the second temperatureadjuster 24 b and the path 18 f, the valve 24 c and the valve 24 d areclosed, and the valve 24 e and the valve 24 f are opened.

Further, though each of the above-described first temperature adjuster24 a and second temperature adjuster 24 b is of a type configured toadjust the temperature of the heat exchange medium flowing therein, eachof the first temperature adjuster 24 a and the second temperatureadjuster 24 b may be implemented by a direct expansion type temperatureadjuster. In case the each of the first and second temperature adjuster24 a and 24 b is the direct expansion type temperature adjuster, eachhas a compressor, a condenser and an expansion valve, and the stage 16serves as an evaporator.

The plasma processing apparatus 10 is equipped with a gas supply line28. Through the gas supply line 28, a heat transfer gas, for example, aHe gas, is supplied from a heat transfer gas supply device into a gapbetween a top surface of the electrostatic chuck 20 and a rear surfaceof the processing target object W.

The plasma processing apparatus 10 is further equipped with an upperelectrode 30. The upper electrode 30 is placed above the stage 16,facing the stage 16. The upper electrode 30 is supported at an upperportion of the chamber main body 12 with an insulating member 32therebetween. The upper electrode 30 may include a ceiling plate 34 anda supporting body 36. The ceiling plate 34 directly faces the chamber 12c, and is provided with a multiple number of gas discharge holes 34 a.This ceiling plate 34 may be made of a conductor or a semiconductorhaving low resistance with low Joule heat.

The supporting body 36 is configured to support the ceiling plate 34 ina detachable manner, and is made of a conductor such as, but not limitedto, aluminum. A gas diffusion space 36 a is formed within the supportingbody 36. Multiple holes 36 b are extended downwards from the gasdiffusion space 36 a to communicate with the gas discharge holes 34 a,respectively. Further, the supporting body 36 is provided with a port 36c through which a gas is introduced into the gas diffusion space 36 a,and a pipeline 38 is connected to this port 36 c.

The pipeline 38 is connected to a gas source group 40 via a valve group42 and a flow rate controller group 44. The gas source group 40 includesa plurality of gas sources for supplying a processing gas into thechamber 12 c. The processing gas contains a fluorocarbon gas and/or ahydrofluorocarbon gas. As an example, the gas source group 40 includes asource of a fluorocarbon gas, a source of a hydrogen gas (H₂ gas), and asource of an oxygen-containing gas. The fluorocarbon gas may be, by wayof non-limiting example, a CF₄ gas. The oxygen-containing gas may be,but not limited to, an oxygen gas (O₂ gas). As another example, the gassource group 40 includes a source of a fluorocarbon gas, a source of ahydrofluorocarbon gas and a source of an oxygen-containing gas. Thefluorocarbon gas may be, for example, a C₄F₈ gas. The hydrofluorocarbongas may be, by way of non-limiting example, a CH₂F₂ gas. Theoxygen-containing gas may be, but not limited to, an oxygen gas (O₂gas). As still another example, the gas source group 40 may additionallyinclude a source of a hydrogen gas (H₂ gas), a source of an one or morehalogen-containing gas and a source of a hydrocarbon gas. For example,the gas source group 40 may include a source of a NF₃ gas as the sourceof the one or more halogen-containing gas. Moreover, the gas sourcegroup 40 may include a source of a CH₄ gas as the source of thehydrocarbon gas.

The valve group 42 includes a plurality of valves, and the flow ratecontroller group 44 includes a plurality of flow rate controllers. Eachof the flow rate controllers may be implemented by a mass flowcontroller or a pressure control type flow rate controller. Each of thegas sources belonging to the gas source group 40 is connected to thepipeline 38 via a corresponding flow rate controller belonging to theflow rate controller group 44 and a corresponding valve belonging to thevalve group 42.

A gas exhaust path, having annular shape when viewed from the top, isformed between the stage 16 and a sidewall of the chamber main body 12.A baffle plate 48 is provided at a portion of this gas exhaust path in avertical direction. The baffle plate 48 may be made of, by way ofexample, an aluminum member coated with ceramics such as Y₂O₃. Thechamber main body 12 is also provided with a gas exhaust opening 12 eunder the baffle plate 48. The gas exhaust opening 12 e is connectedwith a gas exhaust device 50 via a gas exhaust line 52. The gas exhaustdevice 50 includes a pressure controller and a vacuum pump such as aturbo molecular pump. The gas exhaust device 50 is configured todecompress the chamber 12 c to a preset pressure. Further, an opening 12p for carry-in and carry-out of the processing target object W isprovided at the sidewall of the chamber main body 12, and the opening 12p is opened/closed by a gate valve GV.

The plasma processing apparatus 10 further includes a first highfrequency power supply 62 and a second high frequency power supply 64.The first high frequency power supply 62 is configured to generate afirst high frequency power for plasma generation. A frequency of thefirst high frequency power is in a range from 27 MHz to 100 MHz, forexample, 100 MHz. The first high frequency power supply 62 is connectedto the lower electrode 18 via a matching device 66. The matching device66 is equipped with a circuit configured to match an output impedance ofthe first high frequency power supply 62 and an input impedance at aload side (lower electrode 18 side). The first high frequency powersupply 62 may be connected to the upper electrode 30 via the matchingdevice 66.

The second high frequency power supply 64 is configured to generate asecond high frequency power for ion attraction into the processingtarget object W. A frequency of the second high frequency power rangesfrom 400 kHz to 13.56 MHz, for example, 3 MHz. The second high frequencypower supply 64 is connected to the lower electrode 18 via a matchingdevice 68. The matching device 68 is equipped with a circuit configuredto match an output impedance of the second high frequency power supply64 and the input impedance at the load side (lower electrode 18 side).

The plasma processing apparatus 10 may further include a control unitCU. The control unit CU is implemented by a computer including aprocessor, a storage unit, an input device, a display device and thelike. The control unit CU is configured to control individual componentsof the plasma processing apparatus 10. In the control unit CU, anoperator can input commands through the input device to manage theplasma processing apparatus 10. Further, an operational status of theplasma processing apparatus 10 can be visually displayed on the displaydevice. Further, the storage unit of the control unit CU stores thereinrecipe data and control programs for controlling various processingsperformed in the plasma processing apparatus 10 by the processor. Forexample, the storage unit of the control unit CU stores therein controlprograms for implementing the method MT in the plasma processingapparatus 10 and recipe data.

Now, referring back to FIG. 1, the method MT will be explained for anexample case where the method MT is performed on the processing targetobject W shown in FIG. 2 by using the plasma processing apparatus 10. InFIG. 1, two parallel double lines indicate that two or more of aplurality of processes drawn between the two parallel double lines areperformed in parallel. Hereinafter, reference is also made to FIG. 5 andFIG. 6 as well as FIG. 1. FIG. 5 and FIG. 6 are timing charts regardingthe method MT.

As depicted in FIG. 1, the method MT is begun from a process ST1. In theprocess ST1, a temperature of the electrostatic chuck 20 is set to atemperature equal to or less than −30° C. for main etching to bedescribed later. In the process ST1, the coolant is circulated betweenthe first temperature adjuster 24 a and the path 18 f.

In a subsequent process ST2, the processing target object W is carriedinto the chamber 12 c. In the process ST2, the processing target objectW is placed on and held by the electrostatic chuck 20. Further, theprocess ST1 may be performed after the process ST2.

Then, a process ST3 is performed. In the process ST3, the etching targetfilm EF of the processing target object W is etched. In the process ST3,plasma of the processing gas containing a fluorocarbon gas and/or ahydrofluorocarbon gas is generated in the chamber 12 c. As an example,the processing gas contains a fluorocarbon gas and a hydrogen gas (H₂gas). The fluorocarbon gas may be, by way of example, but notlimitation, a CF₄ gas. As another example, the processing gas contains afluorocarbon gas, a hydrofluorocarbon gas, a hydrogen gas (H₂ gas), anone or more halogen-containing gas and a hydrocarbon gas. For example,the processing gas may contain a CH₂F₂ gas, a C₄F₈ gas, a H₂ gas, a CH₄gas and a NF₃ gas. To elaborate, in the process ST3, the processing gasis supplied into the chamber 12 c from the gas source group 40. Further,an internal pressure of the chamber 12 c is set to a preset pressure bythe gas exhaust device 50. Further, the first high frequency power isoutput from the first high frequency power supply 62 for plasmageneration. As a result, the plasma of the processing gas is generatedwithin the chamber 12 c. Here, when necessary, the second high frequencypower may be supplied to the lower electrode 18 from the second highfrequency power supply 64. In the process ST3, the etching target filmEF is etched by ions and/or radicals in the plasma.

The process ST3 includes a main etching ST31 and an overetching ST32. Inthe main etching ST31, the etching target film EF is etched by the ionsand/or radicals in the plasma of the aforementioned processing gas in astate (see FIG. 5) that the temperature of the electrostatic chuck 20 isset to the temperature equal to or less than −30° C. by the temperaturecontrol device 24. If the etching target film EF is etched by the ionsand/or radicals in the plasma of the aforementioned processing gas inthe state that the temperature of the electrostatic chuck 20, i.e., thetemperature of the processing target object W is set to the temperatureequal or less than −30° C., an etching rate of the etching target filmEF is increased.

The overetching ST32 is performed after the main etching ST31. In casethat the mask MK has the multiple openings, the etching target film EFmay not be etched uniformly under the multiple openings of the mask MKby the etching in the main etching ST31. That is, when the etchingtarget film EF is etched by the main etching ST31 until the underlyinglayer UL under a part of the openings of the mask MK is exposed, theetching target film EF may be slightly left on the underlying layer ULunder another part of the openings of the mask MK. The overetching ST32is performed to etch the etching target film EF left under this anotherpart of the openings of the mask MK so that the etching target film EFis etched uniformly under all the openings of the mask MK.

In the overetching ST32, the etching target film EF is etched by theions and/or the radicals in the plasma of the aforementioned processinggas. In the exemplary embodiment, the overetching ST32 is performed in astate that the temperature of the electrostatic chuck 20, that is, thetemperature of the processing target object W is set to a temperaturehigher than −30° C. and lower than 0° C. by the temperature controldevice 24. Reference may be made to the temperature of the electrostaticchuck, indicated by a dashed dotted line, in a processing time period ofthe overetching ST32 in FIG. 5. If the temperature of the processingtarget object W in the overetching ST32 is higher than the temperatureof the processing target object W in the main etching ST31, the etchingrate of the etching target film EF by the overetching ST32 is reduced.Accordingly, controllability over an etching amount of the etchingtarget film EF can be improved. Further, damage on the underlying layerUL is suppressed. However, it should be noted that the temperature ofthe electrostatic chuck 20 when the overetching ST32 is being performedmay not be limited to the aforementioned temperature higher than −30° C.and lower than 0° C.

Then, in the method MT, a process ST4 is performed. In the process ST4,neutralization of the electrostatic chuck 20 is performed. In theneutralization of the electrostatic chuck 20, a voltage having anopposite polarity to a voltage applied to the electrode of theelectrostatic chuck 20 when the electrostatic chuck 20 is holding theprocessing target object W is applied to the electrode of theelectrostatic chuck 20.

FIG. 7 is a diagram illustrating a state in which a deposit is formed.If the plasma of the aforementioned processing gas is generated, aplasma product containing carbon or a plasma product containing carbonand fluorine is generated. This plasma product adheres to an inner wallsurface of the chamber main body 12 and forms the deposit when theetching of the process ST3 is being performed. Especially, this plasmaproduct is immediately condensed or solidified at a low-temperatureplace, so that a thick deposit is formed. Thus, if the temperatures ofthe electrostatic chuck 20 and the processing target object W aremaintained to be equal to or lower than −30° C. after the completion ofthe etching of the process ST3, a gas generated from the depositadhering to the inner wall surface of the chamber main body 12 may becondensed or solidified on the processing target object W, so that athick deposit is formed thereon. Resultantly, as depicted in FIG. 7, adeposit DP is formed on the inner wall surface of the chamber main body12, a surface of the stage 16 and a surface of the processing targetobject W.

Here, an experiment conducted to investigate the formation of thedeposit will be explained. In the experiment, the main etching ST31 isperformed in the plasma processing apparatus 10, and a deposition rateof the deposit on the inner wall surface of the chamber main body 12 ismeasured. In this experiment, the temperature of the electrostatic chuck20 when the main etching ST31 is being performed is varied as aparameter. In the main etching ST31 of the experiment, a pressure of thechamber 12 c is set to 60 mTorr (7.999 Pa); a frequency and a power ofthe first high frequency power, 40 MHz and 1 kW; and a power of thesecond high frequency power, 0 kW, and a mixed gas of a H₂ gas (150sccm) and a CF₄ gas (100 sccm) is used as the processing gas.

A graph of FIG. 8 shows the deposition rate of the deposit on the innerwall surface of the chamber main body 12 obtained in the experiment. Onthe graph of FIG. 8, a horizontal axis represents the temperature of theelectrostatic chuck 20 when the main etching ST31 is being performed,and a vertical axis indicates the deposition rate of the deposit. As canbe seen from FIG. 8, the deposition rate when the temperature of theelectrostatic chuck 20 is −60° C. when the main etching ST31 is beingperformed is about twice as high as the deposition rate when thetemperature of the electrostatic chuck 20 is 25° C. when the mainetching ST31 is being performed. Accordingly, it is found out that thethick deposit DP is formed within the chamber main body 12 in theprocess ST3 including the main etching ST31 in which the temperature ofthe electrostatic chuck 20 is set to be equal to or lower than −30° C.

The deposit DP formed within the chamber main body 12 is removed by acleaning of a process ST7 to be described later. Since, however, theprocessing target object W is carried out of the chamber 12 c before theprocess ST7 is performed, the deposit DP on the processing target objectW needs to be reduced or removed before the processing target object Wis carried out of the chamber 12 c. For the purpose, a process ST5 isperformed in the method MT. In the process ST5, the temperature of theelectrostatic chuck 20 is raised to be equal to or higher than 0° C.Accordingly, the temperature of the processing target object W is alsoraised to the temperature equal to or higher than 0° C. In the processST5, the second heat exchange medium is circulated between the secondtemperature adjuster 24 b and the path 18 f. If the temperature of theelectrostatic chuck 20 is set to be 0° C. or higher, the amount of thedeposit DP on the processing target object W may be reduced or thedeposit DP may hardly exist on the processing target object W.

In one exemplary embodiment, the process ST5 is performed immediatelyafter the process ST3. To elaborate, the process ST5 is performed duringthe neutralization of the electrostatic chuck 20 in the process ST4.Reference may be made to the temperature of the electrostatic chuck,indicated by a solid line, in a processing time period of the processST4 in FIG. 5. As a result of performing this process ST5, thetemperatures of the electrostatic chuck 20 and the processing targetobject W are raised immediately after the process ST3 is performed.

In another exemplary embodiment, the process ST5 is performedimmediately after the main etching ST31. To elaborate, the process ST5may be performed in parallel with the overetching ST32. Reference may bemade to the temperature of the electrostatic chuck, indicated by adashed line, in the processing time period of the overetching ST32 inFIG. 5. As a result of this process ST5, the temperatures of theelectrostatic chuck 20 and the processing target object W are raisedimmediately after the main etching ST31 is performed.

In the method MT, a process ST6 is subsequently performed. In theprocess ST6, the processing target object W is carried out of thechamber 12 c. When the process ST6 is being performed, the temperatureof the electrostatic chuck 20 is maintained to be equal to or higherthan 0° C., as shown in FIG. 5.

Thereafter, in the method MT, the process ST7 is performed. In theprocess ST7, the cleaning of the inside of the chamber main body 12 isperformed. In the cleaning, plasma of a cleaning gas is generated withinthe chamber 12 c. The cleaning gas includes an oxygen-containing gas.The oxygen-containing gas may be, by way of example, but not limitation,an oxygen gas (O₂ gas), a carbon monoxide gas or a carbon dioxide gas.Since the deposit DP contains carbon or contains carbon and fluorine,the deposit DP is removed by the plasma of this cleaning gas. A timeperiod for this cleaning may be a cause of a reduction of a throughputof a plasma processing in the plasma processing apparatus. Thus, it isdesirable that the time period for the cleaning is short.

Here, an experiment conducted regarding the cleaning will be explained.In this experiment, an organic film as a sample of the deposit DP isetched by generating the plasma of the cleaning gas within the chamberof the plasma processing apparatus 10. In this experiment, thetemperature of the electrostatic chuck 20 is varied as a parameter. Inthis experiment, a pressure of the chamber 12 c is set to 400 mTorr(53.33 Pa); a frequency and a power of the first high frequency power,40 MHz and 1 kW; and a power of the second high frequency power, 0 kW,and an O₂ gas (100 sccm) is used as the cleaning gas.

In this experiment, an etching rate of the organic film is measured.FIG. 9 shows the result. In FIG. 9, a horizontal axis represents thetemperature of the electrostatic chuck 20 when the etching of theorganic film is being performed, and a vertical axis indicates theetching rate of the organic film. As can be seen from FIG. 9, when thetemperature of the electrostatic chuck 20 is low when the etching of theorganic film is being performed, the etching rate of the organic film isvery low. Meanwhile, if the temperature of the electrostatic chuck 20when the etching of the organic film is being performed is set to be 0°C. or higher, the etching rate of the organic film is increasedconsiderably. Accordingly, it is found out that the temperature of theelectrostatic chuck 20 needs to be set to be equal to or higher than 0°C. when the process ST7 is being performed.

In one exemplary embodiment, the process ST7 includes, as shown in FIG.5, a process ST71, a process ST72, a process ST73, a process ST74 and aprocess ST75. In the process ST71, a dummy wafer is carried into thechamber 12 c for the cleaning and is held by the electrostatic chuck 20.

In the subsequent process ST72, plasma of a cleaning gas is generatedwithin the chamber 12 c. The cleaning gas includes an oxygen-containinggas. The oxygen-containing gas may be, by way of non-limiting example,an oxygen gas (O₂ gas), a carbon monoxide gas or a carbon dioxide gas.In the process ST72, the cleaning gas is supplied into the chamber 12 cfrom the gas source group 40. Further, the first high frequency power issupplied from the first high frequency power supply 62 for plasmageneration.

In the subsequent process ST73, the neutralization of the electrostaticchuck 20 is performed. This neutralization of the electrostatic chuck 20is the same process as the process ST4. In the process ST74, the dummywafer is carried out of the chamber 12 c.

Then, in the process ST75, plasma of a cleaning gas is generated withinthe chamber 12 c in a state that an object such as the dummy wafer isnot placed on the electrostatic chuck 20. In the process ST75, thecleaning gas is the same gas as the cleaning gas in the process ST72.Further, the generation of the plasma in the process ST75 is performedin the same way as in the process ST72. FIG. 10 is a diagramillustrating a state after the process ST7 is completed. As depicted inFIG. 10, by performing the process ST7, the deposit DP is removed fromthe inner wall surface of the chamber main body 12 and the surface ofthe stage 16.

In this exemplary embodiment, as shown in FIG. 5, the temperature of theelectrostatic chuck 20 is maintained to be equal to or higher than 0° C.until a certain time within a processing time of the process ST75 afterthe temperature of the electrostatic chuck 20 is increased in theprocess ST5. When the temperature of the electrostatic chuck 20 ismaintained to be equal to or higher than 0° C., the second heat exchangemedium is supplied into the path 18 f from the second temperatureadjuster 24 b. Since the temperature of the electrostatic chuck 20 isset to be equal to or higher than 0° C. during the cleaning of theprocess ST7, a removing rate of the deposit DP is increased.Accordingly, the time period for the cleaning of the inside of thechamber main body 12 is shortened.

In another exemplary embodiment, as shown in FIG. 6, the process ST7includes only the process ST75. That is, immediately after theprocessing target object W is carried out of the chamber 12 c in theprocess ST6, the process ST75 is performed. In the process ST75, theplasma of the cleaning gas is generated within the chamber 12 c in astate that an object such as the dummy wafer is not placed on theelectrostatic chuck 20. As depicted in FIG. 6, the temperature of theelectrostatic chuck 20 is maintained to be equal to or higher than 0° C.until a certain time within a processing time of the process ST75 afterthe temperature of the electrostatic chuck 20 is increased in theprocess ST5. When the temperature of the electrostatic chuck 20 ismaintained to be equal to or higher than 0° C., the second heat exchangemedium is supplied into the path 18 f from the second temperatureadjuster 24 b. Since the temperature of the electrostatic chuck 20 isset to be equal to or higher than 0° C. during the cleaning of theprocess ST7, the removing rate of the deposit DP is increased.Accordingly, the time period for the cleaning of the inside of thechamber main body 12 is shortened.

Referring back to FIG. 1, in the method MT, a process ST8 is thenperformed. In the process ST8, it is determined whether anotherprocessing target object is to be processed. In case of processinganother processing target object, the processing is performed again fromthe process ST1. Meanwhile, if another processing target object is notprocessed, the method MT is ended.

As stated above, in the exemplary embodiment, since the temperature ofthe electrostatic chuck 20 and, ultimately, the temperature of theprocessing target object W are raised to the temperature equal to orhigher than 0° C. immediately after the process ST3 or the main etchingST31 is performed, the deposit DP on the processing target object W isremoved or the amount thereof is reduced by the time when the processingtarget object W is carried out of the chamber.

In the exemplary embodiment, the process ST5 is performed when theprocess ST4 is performed, as described above. That is, the process ST5is performed in parallel with the neutralization of the electrostaticchuck 20 which is performed in a time period between the process ST3 andthe process ST6. Accordingly, an additional time period only for raisingthe temperature of the electrostatic chuck 20 is not necessary.Therefore, a time period from the end of the etching of the process ST3to the start of the process ST7 can be shortened.

In another exemplary embodiment, the process ST5 is performed when theoveretching ST32 is performed, as stated above. That is, the raising ofthe temperature of the electrostatic chuck 20 in the process ST5 isperformed in parallel with the overetching ST32. Accordingly, anadditional time period only for raising the temperature of theelectrostatic chuck 20 is not necessary. Therefore, the time period fromthe end of the etching of the process ST3 to the start of the processST7 can be shortened.

Furthermore, by using the temperature control device 24, when startingthe performing of the process ST5, it is possible to switch the heatexchange medium supplied into the path 18 f at a high speed from thefirst heat exchange medium of the low temperature to the second heatexchange medium of the high temperature.

Now, a plasma processing apparatus according to another exemplaryembodiment that can be used in performing the method MT will beexplained. FIG. 11 is a diagram schematically illustrating the plasmaprocessing apparatus according to another exemplary embodiment that canbe used in performing the method shown in FIG. 1. A plasma processingapparatus 100 shown in FIG. 11 is configured as a capacitively coupledplasma processing apparatus. The plasma processing apparatus 100includes a chamber main body 112 and a stage 116. The chamber main body112 has a substantially cylindrical shape, and an internal space of thechamber main body 112 is configured as a chamber 112 c. The chamber mainbody 112 is made of, by way of example, aluminum. A film made of ceramicsuch as an yttrium oxide film, which has plasma resistance, is formed ona surface of the chamber main body 112 at a chamber 112 c side. Thechamber main body 112 is grounded. Further, an opening 112 p throughwhich a processing target object W is carried into/out of the chamber112 c is provided at a side wall of the chamber main body 112. Thisopening 112 p is configured to be opened/closed by a gate valve GV.

The stage 116 is configured to support the processing target object Wwithin the chamber 112 c. The stage 116 has a function of attracting theprocessing target object W and adjusting a temperature of the processingtarget object W, and has a structure in which a high frequency power issent to a base of an electrostatic chuck. Details of this stage 116 willbe discussed later.

The plasma processing apparatus 100 is further equipped with an upperelectrode 130. The upper electrode 130 is placed within a top opening ofthe chamber main body 112 and is arranged to be substantially parallelto a lower electrode of the stage 116. An insulating supporting member132 is provided between the upper electrode 130 and the chamber mainbody 112.

The upper electrode 130 includes a ceiling plate 134 and a supportingbody 136. The ceiling plate 134 has a substantially disk shape. Theceiling plate 134 may have conductivity. Further, the ceiling plate 134is made of, by way of non-limiting example, silicon. Alternatively, theceiling plate 134 is made of aluminum, and a ceramic film having plasmaresistance is formed on a surface of the ceiling plate 134. The ceilingplate 134 is provided with a multiple number of gas discharge holes 134a. These gas discharge holes 134 a are extended in a substantiallyvertical direction.

The supporting body 136 is configured to support the ceiling plate 134in a detachable manner, and is made of, by way of non-limiting example,aluminum. A gas diffusion space 136 a is formed within the supportingbody 136. Multiple holes 136 b are extended from the gas diffusion space136 a to communicate with the gas discharge holes 134 a, respectively. Apipeline 138 is connected to the gas diffusion space 136 a via a port136 c. A gas source group 40 is connected to this pipeline 138 via avalve group 42 and a flow rate controller group 44 in the same way as inthe plasma processing apparatus 10.

The plasma processing apparatus 100 is further equipped with a gasexhaust device 150. The gas exhaust device 150 includes one or morevacuum pumps such as turbo molecular pumps and a pressure controller.This gas exhaust device 150 is connected to a gas exhaust port formed atthe chamber main body 112.

The plasma processing apparatus 100 further includes a control unit MCU.The control unit MCU has the same configuration as the control unit CUof the plasma processing apparatus 10. Recipe data and a control programfor controlling various processings performed in the plasma processingapparatus 100 by the processor are stored in a storage unit of thecontrol unit MCU. By way of example, recipe data and control programsfor implementing the method MT in the plasma processing apparatus 100are stored in the storage unit of the control unit MCU.

Now, with reference to FIG. 12 and FIG. 13 in addition to FIG. 11, thestage 116 and constituent components of the plasma processing apparatus100 belonging to the stage 116 will be discussed in detail. FIG. 12 isan enlarged sectional view illustrating a part of the stage of theplasma processing apparatus shown in FIG. 11, and FIG. 13 is an enlargedsectional view illustrating another part of the stage of the plasmaprocessing apparatus illustrated in FIG. 11.

The stage 116 includes a cooling table 117 and an electrostatic chuck120. The cooling table 117 is supported by a supporting member 114upwardly extended from a bottom portion of the chamber main body 112.This supporting member 114 is implemented by an insulating member and ismade of, by way of non-limiting example, aluminum oxide (alumina).Further, the supporting member 114 has a substantially cylindricalshape.

The cooling table 117 is made of a conductive metal, for example,aluminum. The cooling table 117 has a substantially disk shape. Thecooling table 117 has a central portion 117 a and a peripheral portion117 b. The central portion 117 a has a substantially disk shape. Thecentral portion 117 a provides a first top surface 117 c of the coolingtable 117. The first top surface 117 c is of a substantially circularshape.

The peripheral portion 117 b is continuous with the central portion 117a, and is extended in a circumferential direction (a circumferentialdirection with respect to a vertically extended axis line Z) at anoutside of the central portion 117 a in a diametric direction (a radialdirection with respect to the axis line Z). The peripheral portion 117 bprovides a bottom surface 117 d of the cooling table 117 along with thecentral portion 117 a. Further, the peripheral portion 117 b provides asecond top surface 117 e. The second top surface 117 e is a band-shapedsurface, and is located outside the first top surface 117 c in thediametric direction and extended in the circumferential direction.Further, in the vertical direction, the second top surface 117 e islocated closer to the bottom surface 117 d than the first top surface117 c is.

The cooling table 117 is connected with a power feed body 119. The powerfeed body 119 is, for example, a power feed rod and is connected to thebottom surface 117 d of the cooling table 117. The power feed body 119is made of aluminum or an aluminum alloy. The power feed body 119 isconnected to a first high frequency power supply 62 via a matchingdevice 66. Further, the power feed body 119 is connected with a secondhigh frequency power supply 64 via a matching device 68.

The cooling table 117 is provided with a path 117 f for a coolant. Thepath 117 f is extended in, for example, a spiral shape within thecooling table 117. The coolant is supplied into the path 117 f from achiller unit TU. The chiller unit TU constitutes a part of a temperaturecontrol device according to the exemplary embodiment. The coolantsupplied into the path 117 f is returned back to the chiller unit TU.Here, the coolant supplied into the path 117 f may be of a type in whichheat is absorbed by vaporization thereof to perform cooling. Thiscoolant may be, for example, a hydrofluorocarbon-based coolant.

The electrostatic chuck 120 is provided on the cooling table 117. Toelaborate, the electrostatic chuck 120 is provided on the first topsurface 117 c of the cooling table 117. The electrostatic chuck 120 hasa base 121 and an attracting member 123. The base 121 constitutes alower electrode and is provided on the cooling table 117. The base 121has conductivity. By way of non-limiting example, the base 121 may bemade of ceramic such as aluminum nitride or silicon carbide havingconductivity, or made of a metal (e.g., titanium).

The base 121 has a substantially disk shape. The base 121 has a centralportion 121 a and a peripheral portion 121 b. The central portion 121 ahas a substantially disk shape. The central portion 121 a provides afirst top surface 121 c of the base 121. The first top surface 121 c isof a substantially circular shape.

The peripheral portion 121 b is continuous with the central portion 121a and is extended in a circumferential direction at an outside of thecentral portion 121 a in a diametric direction. The peripheral portion121 b provides a bottom surface 121 d of the base 121 along with thecentral portion 121 a. Further, the peripheral portion 121 b provides asecond top surface 121 e. The second top surface 121 e is a band-shapedsurface and extended in the circumferential direction at an outside ofthe first top surface 121 c in the diametric direction. Further, in thevertical direction, the second top surface 121 e is located closer tothe bottom surface 121 d than the first top surface 121 c is.

The attracting member 123 is provided on the base 121. The attractingmember 123 is coupled to the base 121 by metal bonding with a metalprovided between the attracting member 123 and the base 121. Theattracting member 123 has a substantially disk shape and is made ofceramic. The ceramic forming the attracting member 123 may be one havinga volume resistivity of 1×10¹⁵ Ω·cm or more in a temperature range froma room temperature (e.g., 20° C.) to 400° C. As an example of thisceramic, aluminum oxide (alumina) may be used.

The electrostatic chuck 120 includes a plurality of concentric regionsRN with respect to the axis line Z, that is, a central axis line of theelectrostatic chuck 120. In the present exemplary embodiment, theelectrostatic chuck 120 includes a first region R1, a second region R2and a third region R3. The first region R1 intersects with the axis lineZ, and the third region R3 is a region including an edge of theelectrostatic chuck 120. The second region R2 is located between thefirst region R1 and the third region R3. In the present exemplaryembodiment, the first region R1 ranges up to a radius of 120 mm from acenter of the electrostatic chuck 120; the second region R2 ranges fromthe radius of 120 mm to a radius of 135 mm of the electrostatic chuck120; and the third region R3 ranges from the radius of 135 mm to aradius of 150 mm of the electrostatic chuck 120. Further, the number ofthe regions of the electrostatic chuck 120 may be equal to or largerthan 1.

The attracting member 123 of the electrostatic chuck 120 has anattraction electrode 125 embedded therein. The attraction electrode 125is a film-shaped electrode and is electrically connected with a DC powersupply 22 via a switch. If a DC voltage is applied to the attractionelectrode 125 from the DC power supply 22, the attracting member 123generates an electrostatic force such as a Coulomb force and holds theprocessing target object W with this electrostatic force.

The attracting member 123 is additionally equipped with a multiplenumber of heaters HN. These heaters HN constitute a part of thetemperature control device according to the exemplary embodiment, andare respectively provided in the multiple regions RN of theelectrostatic chuck. In the present exemplary embodiment, the multipleheaters HN include a first heater 156, a second heater 157 and a thirdheater 158. The first heater 156 is provided in the first region R1; thesecond heater 157, in the second region R2; and the third heater 158, inthe third region R3.

The individual heaters HN are connected to a heater power supply 161. Inthe present exemplary embodiment, a filter 163 a is provided between thefirst heater 156 and the heater power supply 161 to suppress the highfrequency power from being introduced into the heater power supply 161.A filter 163 b is provided between the second heater 157 and the heaterpower supply 161 to suppress the high frequency power from beingintroduced into the heater power supply 161. Further, a filter 163 c isprovided between the third heater 158 and the heater power supply 161 tosuppress the high frequency power from being introduced into the heaterpower supply 161.

Multiple first elastic members EM1 are provided between the base 121 andthe cooling table 117. The first elastic members EM1 are configured toallow the electrostatic chuck 120 to be upwardly spaced apart from thecooling table 117. Each of the first elastic members EM1 is an O-ring.The individual first elastic members EM1 have different diameters andare arranged concentrically with respect to the axis line Z. Further,the first elastic members EM1 are located under boundaries between theadjacent regions of the electrostatic chuck 120 and under the edge ofthe electrostatic chuck 120. In the present exemplary embodiment, thefirst elastic members EM1 include an elastic member 165, an elasticmember 167 and an elastic member 169. The elastic member 165 is providedunder a boundary between the first region R1 and the second region R2;the elastic member 167, under a boundary between the second region R2and the third region R3; and the elastic member 169, under the edge ofthe electrostatic chuck 120.

The individual first elastic member EM1 are partially placed in groovesprovided on the first top surface 117 c of the cooling table 117 and incontact with the first top surface 117 c and the bottom surface 121 d ofthe base 121. These first elastic members EM1 define, along with thecooling table 117 and the base 121, a plurality of sealed heat transferspaces DSN between the first top surface 117 c of the cooling table 117and the bottom surface 121 d of the base 121. These heat transfer spacesDSN are respectively extended under the multiple regions RN of theelectrostatic chuck 120 and separated from each other. In the exemplaryembodiment, the heat transfer spaces DSN include a first heat transferspace DS1, a second heat transfer space DS2 and a third heat transferspace DS3. The first heat transfer space DS1 is located inside theelastic member 165; the second heat transfer space DS2, between theelastic member 165 and the elastic member 167; and the third heattransfer space DS3, between the elastic member 167 and the elasticmember 169. As will be described later, a gas source GS of a heattransfer gas (for example, a He gas), a chiller unit TU and a gasexhaust device VU are connected to the heat transfer spaces DSNselectively via a pipeline system PS. Further, a length of each heattransfer space DSN in a vertical direction is set to be in a range from,but not limited to, 0.1 mm to 2.0 mm.

In the present exemplary embodiment, each of the first elastic membersEM1 has heat resistivity higher than heat resistivity of each of theheat transfer spaces DSN in which the He gas is supplied. The heatresistivity of each heat transfer space DSN depends on a heatconductivity of the heat transfer gas, a length of the correspondingheat transfer space DSN in the vertical direction and an area thereof.Further, the heat resistivity of each first elastic member EM1 dependson a heat conductivity of the corresponding first elastic member EM1, athickness of the corresponding first elastic member EM1 in the verticaldirection and an area thereof. Thus, a material, the thickness and thearea of each of the first elastic members EM1 are determined based onthe heat resistivity of the corresponding heat transfer space DSN.Furthermore, the first elastic members EM1 may be required to have lowheat conductivity and high heat resistance. Thus, the first elasticmembers EM1 may be formed of, by way of non-limiting example,perfluoroelastomer.

The stage 116 may be further equipped with a fastening member 171. Thefastening member 171 is made of a metal and is configured to clamp thebase 121 and the first elastic members EM1 between the fastening member171 and the cooling table 117. The fastening member 171 is made of amaterial having low heat conductivity, for example, titanium to suppressheat conduction between the base 121 and the cooling table 117 throughthe fastening member 171.

In the present exemplary embodiment, the fastening member 171 has acylindrical portion 171 a and an annular portion 171 b. The cylindricalportion 171 a has a substantially cylindrical shape, and has a firstbottom surface 171 c at a bottom end thereof. The first bottom surface171 c is a band-shaped surface extended in the circumferential directionthereof.

The annular portion 171 b has a substantially annular plate shape and isextended from the cylindrical portion 171 a inwardly in the diametricdirection to be continuous with an upper inner periphery of thecylindrical portion 171 a. This annular portion 171 b provides a secondbottom surface 171 d. The second bottom surface 171 d is a band-shapedsurface extended in the circumferential direction thereof.

The fastening member 171 is placed such that the first bottom surface171 c is in contact with the second top surface 117 e of the coolingtable 117 and the second bottom surface 171 d is in contact with thesecond top surface 121 e of the base 121. Further, the fastening member171 is fixed to the peripheral portion 117 b of the cooling table 117 bya screw 173. By adjusting screwing of this screw 173 into the fasteningmember 171, a pressed amount of the first elastic members EM1 isadjusted, so that the length of the heat transfer spaces DSN in thevertical direction is adjusted.

In the exemplary embodiment, a second elastic member 175 is providedbetween a bottom surface of an inner peripheral portion of the annularportion 171 b of the fastening member 171 and the second top surface 121e of the base 121. The second elastic member 175 is implemented by anO-ring and is configured to suppress a particle (e.g., metal powder)that might be generated by a friction between the second bottom surface171 d of the fastening member 171 and the second top surface 121 e ofthe base 121 from being moved toward the attracting member 123.

Furthermore, the second elastic member 175 generates a reaction forcesmaller than a reaction force generated by the first elastic membersEM1. That is, the first elastic members EM1 are configured such that thereaction force generated by the first elastic members EM1 is larger thanthe reaction force generated by the second elastic member 175. Inaddition, this second elastic member 175 may be made of a materialhaving high heat resistance and low heat conductivity, for example,perfluoroelastomer.

A heater 176 is provided on the fastening member 171. This heater 176 isextended in the circumferential direction and connected to a heaterpower supply 161 via a filter 178. The filter 178 is provided tosuppress the high frequency power from being introduced into the heaterpower supply 161.

The heater 176 is provided between a first film 180 and a second film182. The first film 180 is located closer to the fastening member 171than the second film 182 is. The first film 180 has heat conductivitylower than that of the second film 182. By way of example, the firstfilm 180 may be a thermally sprayed zirconia-based film, and the secondfilm 182 may be a thermally sprayed yttrium oxide (yttria)-based film.Further, the heater 176 may be a thermally sprayed tungsten film.

A focus ring FR is provided on the second film 182. The focus ring FRmay be heated by heat from the heater 176. Further, most of heat fluxfrom the heater 176 flows toward the second film 182 than the first film180, and flows toward the focus ring FR through the second film 182.Accordingly, the focus ring FR is efficiently heated.

Furthermore, outer side surfaces of the fastening member 171 and thecooling table 117 of the stage 116 and so forth are covered with one ormore insulating members 186. The one or more insulating members 186 maybe made of, by way of example, but not limitation, aluminium oxide orquartz.

In addition, as illustrated in FIG. 13, a gas line 190 through which theheat transfer gas (e.g., He gas) is supplied into a gap between theprocessing target object W and the attracting member 123 is provided inthe electrostatic chuck 120 and the cooling table 117 of the stage 116.The gas line 190 is connected to a heat transfer gas supply unit 191.

As depicted in FIG. 13, the gas line 190 includes a gas line 190 a, agas line 190 b and a gas line 190 c. The gas line 190 a is formed in theattracting member 123. Further, the gas line 190 c is formed in thecooling table 117. The gas line 190 a and the gas line 190 c areconnected to each other with the gas line 190 b therebetween. The gasline 190 b is implemented by a sleeve 192. This sleeve 192 is asubstantially cylindrical member, and at least a surface thereof hasinsulation property. This surface of the sleeve 192 is made of ceramic.As an example, the sleeve 192 is made of insulating ceramic. By way ofexample, the sleeve 192 is made of aluminium oxide (alumina). As anotherexample, the sleeve 192 may be implemented by a metal member having asurface on which insulation treatment is performed. For example, thesleeve 192 may have a main body made of aluminium and an alumite filmformed on a surface of the main body.

In the base 121 and the cooling table 117, an accommodation space foraccommodating the sleeve 192 is formed. A film 194 made of insulatingceramic is formed on a surface 121 f of the base 121 which partitionsand forms this accommodation space. The film 194 may be, by way ofexample, but not limitation, a thermally sprayed aluminium oxide(alumina) film.

A third elastic member 196 is provided between the film 194 and thecooling table 117 to hermetically seal the accommodation space of thesleeve 192. The third elastic member 196 is implemented by an O-ring andhas insulation property. The third elastic member 196 may be made of, byway of non-limiting example, perfluoroelastomer. Further, a fourthelastic member 198 is provided at an outside of the third elastic member196. The fourth elastic member 198 is an O-ring and in contact with thefirst top surface 117 c of the cooling table 117 and the bottom surface121 d of the base 121 while sealing the heat transfer space (forexample, the first heat transfer space DS1). The fourth elastic member198 may be made of, by way of example, but not limitation,perfluoroelastomer.

As stated above, in the stage 116, the cooling table 117 and the base121 are spaced apart from each other by the first elastic members EM1.Further, in this stage 116, no adhesive is used to couple the base 121and the attracting member 123. Accordingly, the temperature of theelectrostatic chuck 120 can be set to be high. Further, since heattransfer between the electrostatic chuck 120 and the cooling table 117is achieved through the heat transfer gas supplied into the heattransfer spaces DSN, it is also possible to set the temperature of theelectrostatic chuck 120 to be low. Furthermore, in this stage 116, apower feed route for the high frequency power to the base 121 of theelectrostatic chuck 120 is secured by the power feed body 119, thecooling table 117 and the fastening member 171. Moreover, since thepower feed body 119 is not directly connected to the base 121 of theelectrostatic chuck 120 but connected to the cooling table 117,aluminium or an aluminium alloy can be used as a material for the powerfeed body 119. Accordingly, even in case of supplying the high frequencypower of the high frequency equal to or higher than 13.56 MHz, a loss ofthe high frequency power in the power feed body 119 is suppressed.

In addition, as described above, the second elastic member 175 isprovided between the bottom surface of the inner peripheral portion ofthe annular portion 171 b of the fastening member 171 and the second topsurface 121 e of the base 121. Since the second top surface 121 e of theperipheral portion 121 b of the base 121 and the second bottom surface171 d of the fastening member 171 are in contact with each other,friction is generated at the contact point therebetween, so that theparticle (e.g., metal powder) may be generated thereat. Even when thisparticle is generated, the second elastic member 175 suppresses theparticle from adhering to the attracting member 123 and the processingtarget object W placed on the corresponding attracting member 123.

Further, the first elastic members EM1 are configured such that thereaction force generated by these first elastic members EM1 is largerthan the reaction force generated by the second elastic member 175.Accordingly, the electrostatic chuck 120 can be securely spaced from thecooling table 117.

Furthermore, each of the first elastic members EM1 is configured to havethe heat resistance higher than the heat resistance of the correspondingheat transfer space DSN when the He gas is supplied in the correspondingheat transfer space DSN. Further, these first elastic members EM1 aremade of, by way of example, perfluoroelastomer. With these first elasticmembers EM1, the heat conduction through the heat transfer spaces DSN ismore dominant than heat conduction through the first elastic members EM1between the electrostatic chuck 120 and the cooling table 117. Thus, thetemperature distribution of the electrostatic chuck 120 can beuniformed.

Additionally, the gas line 190 for the heat transfer gas supplied intothe gap between the processing target object W and the attracting member123 is formed without using any adhesive. Further, the surface 121 f ofthe base 121, which forms the accommodation space in which the sleeve192 as a part of the gas line 190 is placed, is covered with the film194, and the third elastic member 196 having the insulation property isprovided between the film 194 and the cooling table 117 to seal thecorresponding accommodation space. With this configuration, introductionof the plasma into the gap between the base 121 and the cooling table117 and a resultant dielectric breakdown of the base 121 can besuppressed.

Furthermore, according to the plasma processing apparatus 100 having theabove-described stage 116, a plasma processing can be performed on theprocessing target object W in a wide temperature range from a lowtemperature to a high temperature.

Now, a pipeline system PS that can be adopted in the plasma processingapparatus 100 will be explained. FIG. 14 is a diagram illustrating anexample configuration of the pipeline system. The pipeline system PSshown in FIG. 14 constitutes a part of the temperature control deviceaccording to the exemplary embodiment, and has a multiple number ofvalves. The pipeline system PS is configured to connect the gas sourceGS, the chiller unit TU and the gas exhaust device VU selectively toeach of the heat transfer spaces DSN and configured to switch aconnection and a disconnection between the chiller unit TU and the path117 f. Below, the description will be provided for the example where theheat transfer spaces DSN include three heat transfer spaces (the firstheat transfer space DS1, the second heat transfer space DS2, and thethird heat transfer space DS3). Here, however, it should be noted thatthe number of the heat transfer spaces DSN may not be particularlylimited, and may be one or more as long as the number of the heattransfer spaces DSN corresponds to the number of the regions RN of theelectrostatic chuck 120.

The pipeline system PS includes a line L21, a line L22, a valve V21 anda valve V22. One end of the line L21 is connected to the chiller unitTU, and the other end of the line L21 is connected to the path 117 f.The valve V21 is provided at a part of the line L21. One end of the lineL22 is connected to the chiller unit TU, and the other end of the lineL22 is connected to the path 117 f. The valve V22 is provided at a partof the line L22. If the valve V21 and the valve V22 are opened, thecoolant is supplied from the chiller unit TU into the path 117 f throughthe line L21. The coolant supplied into the path 117 f is returned backinto the chiller unit TU through the line L22.

Further, the pipeline system PS further includes a pressure controller104 a, a line Lila, a line L12 a, a line L13 a, a line L14 a, a line L15a, a line L17 a, a line L31 a, a line L32 a, a valve V11 a, a valve V12a, a valve V13 a, a vale V14 a, a valve V15 a, a valve V31 a and a valveV32 a.

The pressure controller 104 a is connected to the gas source GS. One endof the line Lila is connected to the pressure controller 104 a. Thevalve Vila is provided at a part of the line Lila. One end of the lineL15 a is connected to the first heat transfer space DS1, and the otherend of the line L15 a is connected to the gas exhaust device VU. Thevalve V15 a is provided at a part of the line L15 a.

One end of the line L12 a is connected to the other end of the lineLila. The other end of the line L12 a is connected to a part of the lineL15 a on the side of the first heat transfer space DS1 with respect tothe valve V15 a. The valve V12 a is provided at a part of the line L12a. One end of the line L13 a and one end of the line L14 a are alsoconnected to the other end of the line Lila. The valve V13 a is providedat a part of the line L13 a, and the valve V14 a is provided at a partof the line L14 a. The other end of the line L13 a and the other end ofthe line L14 a are connected to each other. One end of the line L17 a isconnected to a connection point between the other end of the line L13 aand the other end of the line L14 a. The other end of the line L17 a isconnected to a part of the line L15 a closer to the valve V15 a than theother end of the line L12 a is close to the valve V15 a.

One end of the line L31 a is connected to a part of the line L21 on theside of the chiller unit TU with respect to the valve V21. The other endof the line L31 a is connected to the first heat transfer space DS1. Thevalve V31 a is provided at a part of the line L31 a. One end of the lineL32 a is connected to a part of the line L22 on the side of the chillerunit TU with respect to the valve V22. The other end of the line L32 ais connected to the first heat transfer space DS1. The valve V32 a isprovided at a part of the line L32 a.

Further, the pipeline system PS additionally includes a pressurecontroller 104 b, a line L11 b, a line L12 b, a line L13 b, a line L14b, a line L15 b, a line L17 b, a line L31 b, a line L32 b, a valve V11b, a valve V12 b, a valve V13 b, a valve V14 b, a valve V15 b, a valveV31 b and a valve V32 b.

The pressure controller 104 b is connected to the gas source GS. One endof the line L11 b is connected to the pressure controller 104 b. Thevalve V11 b is provided at a part of the line L11 b. One end of the lineL15 b is connected to the second heat transfer space DS2, and the otherend of the line L15 b is connected to the gas exhaust device VU.Further, the valve V15 b is provided at a part of the line L15 b.

One end of the line L12 b is connected to the other end of the line L11b. The other end of the line L12 b is connected to a part of the lineL15 b on the side of the second heat transfer space DS2 with respect tothe valve V15 b. The valve V12 b is provided at a part of the line L12b. One end of the line L13 b and one end of the line L14 b are alsoconnected to the other end of the line L11 b. The valve V13 b isprovided at a part of the line L13 b, and the valve V14 b is provided ata part of the line L14 b. The other end of the line L13 b and the otherend of the line L14 b are connected to each other. One end of the lineL17 b is connected to a connection point between the other end of theline L13 b and the other end of the line L14 b. The other end of theline L17 b is connected to a part of the line L15 b closer to the valveV15 b than the other end of the line L12 b is close to the valve V15 b.

One end of the line L31 b is connected to a part of the line L21 on theside of the chiller unit TU with respect to the valve V21. The other endof the line L31 b is connected to the second heat transfer space DS2.The valve V31 b is provided at a part of the line L31 b. One end of theline L32 b is connected to a part of the line L22 on the side of thechiller unit TU with respect to the valve V22. The other end of the lineL32 b is connected to the second heat transfer space DS2. The valve V32b is provided at a part of the line L32 b.

Further, the pipeline system PS further includes a pressure controller104 c, a line L11 c, a line L12 c, a line L13 c, a line L14 c, a lineL15 c, a line L17 c, a line L31 c, a line L32 c, a valve V11 c, a valveV12 c, a valve V13 c, a valve V14 c, a valve V15 c, a valve V31 c and avalve V32 c.

The pressure controller 104 c is connected to the gas source GS. One endof the line L11 c is connected to the pressure controller 104 c. Thevalve V11 c is provided at a part of the line L11 c. One end of the lineL15 c is connected to the third heat transfer space DS3, and the otherend of the line L15 c is connected to the gas exhaust device VU.Further, the valve V15 c is provided at a part of the line L15 c.

One end of the line L12 c is connected to the other end of the line L11c. The other end of the line L12 c is connected to a part of the lineL15 c on the side of the third heat transfer space DS3 with respect tothe valve V15 c. The valve V12 c is provided at a part of the line L12c. One end of the line L13 c and one end of the line L14 c are alsoconnected to the other end of the line L11 c. The valve V13 c isprovided at a part of the line L13 c, and the valve V14 c is provided ata part of the line L14 c. The other end of the line L13 c and the otherend of the line L14 c are connected to each other. One end of the lineL17 c is connected to a connection point between the other end of theline L13 c and the other end of the line L14 c. The other end of theline L17 c is connected to a part of the line L15 c closer to the valveV15 c than the other end of the line L12 c is close to the valve V15 c.

One end of the line L31 c is connected to a part of the line L21 on theside of the chiller unit TU with respect to the valve V21. The other endof the line L31 c is connected to the third heat transfer space DS3. Thevalve V31 c is provided at a part of the line L31 c. One end of the lineL32 c is connected to a part of the line L22 on the side of the chillerunit TU with respect to the valve V22. The other end of the line L32 cis connected to the third heat transfer space DS3. The valve V32 c isprovided at a part of the line L32 c.

In the pipeline system PS, when the valve V21 and the valve V22 areopened, the coolant is circulated between the chiller unit TU and thepath 117 f. Meanwhile, when the valve V21 and the valve V22 are closed,the coolant is not supplied into the path 117 f from the chiller unitTU.

Further, when the valve V31 a, the valve V32 a, the valve V31 b, thevalve V32 b, the valve V31 c and the valve V32 c are opened, the coolantis circulated between the chiller unit TU and the heat transfer spacesDSN (DS1, DS2 and DS3). Furthermore, when the coolant is supplied intothe heat transfer spaces DSN (DS1, DS2 and DS3), the valve V11 a, thevalve V12 a, the valve V13 a, the valve V14 a, the valve V15 a, thevalve V11 b, the valve V12 b, the valve V13 b, the valve V14 b, thevalve V15 b, the valve V11 c, the valve V12 c, the valve V13 c, thevalve V14 c and the valve V15 c are closed. Meanwhile, when the valveV31 a, the valve V32 a, the valve V31 b, the valve V32 b, the valve V31c and the valve V32 c are closed, the coolant is not supplied into theheat transfer spaces DSN (DS1, DS2 and DS3) from the chiller unit TU.

Moreover, when the valve V11 a, the valve V12 a, the valve V11 b, thevalve V12 b, the valve V11 c and the valve V12 c are opened while thevalve V13 a, the valve V14 a, the valve V15 a, the valve V13 b, thevalve V14 b, the valve V15 b, the valve V13 c, the valve V14 c and thevalve V15 c are closed, the heat transfer gas is supplied into the heattransfer spaces DSN (DS1, DS2 and DS3) from the gas source GS.

Furthermore, when the valve V15 a, the valve V15 b and the valve V15 care opened while the valve V11 a, the valve V12 a, the valve V13 a, thevalve V14 a, the valve V11 b, the valve V12 b, the valve V13 b, thevalve V14 b, the valve V11 c, the valve V12 c, the valve V13 c and thevalve V14 c are closed, the heat transfer spaces DSN (DS1, DS2 and DS3)are decompressed by the gas exhaust device VU.

Now, the method MT will be discussed for an example case where themethod MT is applied to the processing target object W shown in FIG. 2by using the plasma processing apparatus 100.

In the process ST1, the temperature of the electrostatic chuck 120 isset to be equal to or lower than −30° C. for main etching to bedescribed later. In the process ST1, the coolant is circulated betweenthe chiller unit TU and the path 117 f, and, also, between the heattransfer spaces DSN and the chiller unit TU. To elaborate, the valveV21, the valve V22, the valve V31 a, the valve V32 a, the valve V31 b,the valve V32 b, the valve V31 c and the valve V32 c are opened, whilethe other valves of the pipeline system PS are closed. In the processST1, the multiple heaters HN are set to be off. That is, in the processST1, no power is supplied to the heaters HN from the heater power supply161.

In the process ST2, the processing target object W is carried into thechamber 112 c. In the process ST2, the processing target object W isplaced on and held by the electrostatic chuck 120.

In the process ST3, the processing gas is supplied into the chamber 112c from the gas source group 40. Further, the pressure of the chamber 112c is set to be a preset pressure by the gas exhaust device 150. Inaddition, the first high frequency power is output from the first highfrequency power supply 62 for plasma generation. Accordingly, the plasmaof the processing gas is generated within the chamber 112 c. Further,when necessary, the second high frequency power may be supplied to thelower electrode of the stage 116 from the second high frequency powersupply 64. In the process ST3, the etching target film EF is etched byions and/or radicals in this plasma.

In the main etching ST31, the etching target film EF is etched by theions and/or radicals in the plasma of the processing gas in the statethat the temperature of the electrostatic chuck 120 is set to be equalto or lower than −30° C. Opening/closing states of the multiple valvesof the pipeline system PS when the main etching ST31 is being performedmay be the same as the opening/closing states of the valves of thepipeline system PS in the process ST1.

The temperature of the electrostatic chuck 120 when the overetching ST32is being performed may be set to be, for example, higher than −30° C.and lower than 0° C. However, the temperature of the electrostatic chuck120 during the overetching ST32 may not be limited to the temperaturehigher than −30° C. and lower than 0° C.

In the process ST4, the neutralization of the electrostatic chuck 120 isperformed. In the neutralization of the electrostatic chuck 120, avoltage having an opposite polarity to the voltage applied to theattraction electrode 125 of the electrostatic chuck 120 when theelectrostatic chuck 120 is holding the processing target object W isapplied to the attraction electrode 125 of the electrostatic chuck 120.

In the process ST5, the temperature of the electrostatic chuck 120 israised to be equal to or higher than 0° C. In the process ST5, the valveV21, the valve V22, the valve V15 a, the valve V15 b and the valve V15 care opened, and the other valves of the pipeline system PS are closed.Further, the power is supplied from the heater power supply 161 to themultiple heaters HN such that the corresponding heaters HN generateheat. In the process ST5, the heat transfer spaces DSN are decompressedby the gas exhaust device VU. As a result, the heat transfer between theelectrostatic chuck 120 and the cooling table 117 is suppressed.Further, in the process ST5, the heaters HN generate heat. Thus, a timeperiod required to raise the temperature of the electrostatic chuck 120is shortened in the process ST5.

In the process ST6, the processing target object W is carried out of thechamber 112 c. During the process ST6, the temperature of theelectrostatic chuck 120 is maintained to be equal to or higher than 0°C. Further, while maintaining the temperature of the electrostatic chuck120 to be equal to or higher than 0° C. after the process ST5 isperformed, the opening/closing states of the multiple valves of thepipeline system PS may be the same as the opening/closing states of thevalves of the pipeline system PS in the process ST5. Alternatively, thepower is applied to the heaters HN from the heater power supply 161 suchthat the corresponding heaters HN generate heat, and the coolant issupplied from the chiller unit TU into at least either of the heattransfer spaces DSN (DS1, DS2 and DS3) and the path 117 f. The coolantmay be supplied into the path 117 f from the chiller unit TU, and theheat transfer gas may be supplied into the heat transfer spaces DSN(DS1, DS2 and DS3) from the gas source GS.

In the process ST71, the dummy wafer is carried into the chamber 112 cand is held by the electrostatic chuck 120. In the process ST72, theplasma of the cleaning gas is generated within the chamber 112 c. In theprocess ST72, the cleaning gas is supplied into the chamber 112 c fromthe gas source group 40. Further, the first high frequency power issupplied from the first high frequency power supply 62 for plasmageneration. In the process ST73, the neutralization of the electrostaticchuck 120 is performed. In the process ST74, the dummy wafer is carriedout of the chamber 112 c. In the process ST75, the plasma of thecleaning gas is generated within the chamber 112 c in the state that anobject such as the dummy wafer is not placed on the electrostatic chuck120. In the method MT, the temperature of the electrostatic chuck 120 ismaintained to be equal to or higher than 0° C. until a certain timewithin a processing time of the process ST75 after the process ST5 isperformed. Accordingly, the time period for the cleaning of the processST7 is shortened.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting. The scope of the inventive concept is defined by thefollowing claims and their equivalents rather than by the detaileddescription of the exemplary embodiments. It shall be understood thatall modifications and embodiments conceived from the meaning and scopeof the claims and their equivalents are included in the scope of theinventive concept.

The claims of the present application are different and possibly, atleast in some aspects, broader in scope than the claims pursued in theparent application. To the extent any prior amendments orcharacterizations of the scope of any claim or cited document madeduring prosecution of the parent could be construed as a disclaimer ofany subject matter supported by the present disclosure, Applicantshereby rescind and retract such disclaimer. Accordingly, the referencespreviously presented in the parent applications may need to berevisited.

We claim:
 1. A plasma processing apparatus, comprising: a chamber; astage, provided in the chamber, on which a target object including anetching film is placed; a temperature adjusting device configured toadjust a temperature of the stage; a processing gas supply deviceconfigured to supply a processing gas containing a fluorocarbon gasand/or a hydrofluorocarbon gas into the chamber; a cleaning gas supplydevice configured to supply a cleaning gas containing an oxygen gas intothe chamber; a plasma generator device configured to generate a plasmain the chamber; and a controller, wherein the controller is configuredto perform: (a) placing the target object on the stage, (b) etching theetching film, comprising: (b1) supplying the processing gas into thechamber from the processing gas supply device, (b2) generating a plasmafrom the processing gas in the chamber, (b3) maintaining the temperatureof the stage to be equal to or lower than −30° C. by the temperatureadjusting device during (b1) and (b2), and (b4) an overetching ofadditionally etching the etching film after (1) and (b2), (c) after (b),removing the target object from the chamber, and (d) after (c), cleaningan inside of the chamber, which comprises: (d1) supplying the cleaninggas into the chamber from the cleaning gas supply device; (d2)generating a plasma from the cleaning gas in the chamber; and (d3)maintaining the temperature of the stage to be equal to or higher than0° C. by the temperature adjusting device during (d1) and (d2), whereinthe controller is configured to perform: prior to (d), raising atemperature of the stage by the temperature adjusting device while theoveretching is being performed during (b4), in order to raise thetemperature of the stage to be equal to or higher than 0° C.
 2. Theplasma processing apparatus of claim 1, wherein the stage comprises anelectrostatic chuck configured to hold the target object placed thereon,and the controller is configured to perform: after (b) and before (c),neutralizing the electrostatic chuck; and prior to (d), raising atemperature of the stage by the temperature adjusting device while theneutralizing of the stage is being performed, in order to raise thetemperature of the stage to be equal to or higher than 0° C.
 3. Theplasma processing apparatus of claim 2, wherein the stage comprises alower electrode in which a path is formed, the electrostatic chuck isprovided on the lower electrode, the temperature adjusting devicecomprises: a first temperature adjuster configured to supply a firstheat exchange medium; and a second temperature adjuster configured tosupply a second heat exchange medium having a temperature higher than atemperature of the first heat exchange medium, and the controller isconfigured to perform: supplying the first heat exchange medium into thepath from the first temperature adjuster while the main etching is beingperformed, and supplying the second heat exchange medium into the pathfrom the second temperature adjuster while the raising of thetemperature of the stage is being performed.
 4. The plasma processingapparatus of claim 2, wherein the stage comprises a cooling table inwhich a path is formed, the electrostatic chuck is provided on thecooling table, a sealed space is provided between the electrostaticchuck and the cooling table, the temperature adjusting device comprises:a heater provided in the electrostatic chuck; a chiller unit configuredto supply a coolant into the path; and a pipeline system configured toconnect one of the chiller unit, a gas exhaust device and a source of aheat transfer gas to the sealed space selectively, and the controller isconfigured to perform: supplying the coolant into the path from thechiller unit and supplying the coolant into the sealed space from thechiller unit when the main etching is being performed; and heating theelectrostatic chuck by the heater and decompressing the sealed space bythe gas exhaust device while the raising of the temperature of the stageis being performed.
 5. The plasma processing apparatus of claim 1,wherein in (d), the plasma from the cleaning gas is generated after adummy wafer is carried into the chamber.
 6. The plasma processingapparatus of claim 1, wherein in (d), the plasma from the cleaning gasis generated after a dummy wafer is carried into the chamber, the dummywafer is carried out from the chamber, and the plasma from the cleaninggas is generated after the dummy wafer is carried out from the chamber.7. The plasma processing apparatus of claim 1, wherein the stagecomprises an electrostatic chuck configured to hold the target objectplaced thereon and a lower electrode in which a path is formed, theelectrostatic chuck is provided on the lower electrode, the temperatureadjusting device comprises: a first temperature adjuster configured tosupply a first heat exchange medium; and a second temperature adjusterconfigured to supply a second heat exchange medium having a temperaturehigher than a temperature of the first heat exchange medium, and thecontroller is configured to perform: supplying the first heat exchangemedium into the path from the first temperature adjuster while the mainetching is being performed, and supplying the second heat exchangemedium into the path from the second temperature adjuster while theraising of the temperature of the stage is being performed.
 8. Theplasma processing apparatus of claim 7, wherein the electrostatic chuckis provided on the lower electrode via a first annular elastic member.9. The plasma processing apparatus of claim 8, wherein each of theelectrostatic chuck and the lower electrode has an annular peripheralportion having a step-shaped portion, and a fastening member, arrangedto fit on each of a top surface of the annular peripheral portion of theelectrostatic chuck and the lower electrode, is fixed to the lowerelectrode with a screw.
 10. The plasma processing apparatus of claim 9,further comprising: a second annular elastic member provided between theelectrostatic chuck and the fastening member.
 11. The plasma processingapparatus of claim 10, wherein the second annular elastic membergenerates a reaction force smaller than a reaction force generated bythe first annular elastic member.
 12. The plasma processing apparatus ofclaim 1, wherein the stage comprises an electrostatic chuck configuredto hold the target object placed thereon and a cooling table in which apath is formed, the electrostatic chuck is provided on the coolingtable, a sealed space is provided between the electrostatic chuck andthe cooling table, the temperature adjusting device comprises: a heaterprovided in the electrostatic chuck; a chiller unit configured to supplya coolant into the path; and a pipeline system configured to connect oneof the chiller unit, a gas exhaust device and a source of a heattransfer gas to the sealed space selectively, and the controller isconfigured to perform: supplying the coolant into the path from thechiller unit and supplying the coolant into the sealed space from thechiller unit when the main etching is being performed; and heating theelectrostatic chuck by the heater and decompressing the sealed space bythe gas exhaust device while the raising of the temperature of the stageis being performed.
 13. The plasma processing apparatus of claim 12,wherein the electrostatic chuck is provided on the cooling table via afirst elastic member which is annular.
 14. The plasma processingapparatus of claim 13, wherein each of the electrostatic chuck and thecooling table has an annular peripheral portion having a step-shapedportion, and a fastening member, arranged to fit on each of a topsurface of the annular peripheral portion of the electrostatic chuck andthe cooling table, is fixed to the cooling table with a screw.
 15. Theplasma processing apparatus of claim 14, further comprising: a secondannular elastic member provided between the electrostatic chuck and thefastening member.
 16. The plasma processing apparatus of claim 15,wherein the second elastic member generates a reaction force smallerthan a reaction force generated by the first elastic member.
 17. Theplasma processing apparatus of claim 1, wherein the stage comprises anelectrostatic chuck configured to hold the target object placed thereon.18. A plasma processing apparatus, comprising: a chamber; a stage,provided in the chamber, on which a target object including an etchingfilm is placed; a temperature adjusting device configured to adjust atemperature of the stage; a processing gas supply device configured tosupply a processing gas containing a fluorocarbon gas and/or ahydrofluorocarbon gas into the chamber; a cleaning gas supply deviceconfigured to supply a cleaning gas containing an oxygen gas into thechamber; a plasma generator device configured to generate a plasma inthe chamber; and a controller, wherein the controller is configured toperform: (a) placing the target object on the stage, (b) etching theetching film, comprising: (b1) supplying the processing gas into thechamber from the processing gas supply device, (b2) generating a plasmafrom the processing gas in the chamber, (b3) maintaining the temperatureof the stage to be equal to or lower than −30° C. by the temperatureadjusting device during (b1) and (b2), and (b4) an overetching ofadditionally etching the etching film after (b1) and (b2), (c) after(b), removing the target object from the chamber, and (d) after (c),cleaning an inside of the chamber, which comprises: (d1) supplying thecleaning gas into the chamber from the cleaning gas supply device; (d2)generating a plasma from the cleaning gas in the chamber; and (d3)maintaining the temperature of the stage to be equal to or higher than0° C. by the temperature adjusting device during (d1) and (d2), whereinthe controller is configured to perform: setting a temperature of thestage to be higher than −30° C. and lower than 0° C. while theoveretching is being performed during (b4).